In nonvolatile semiconductor memory devices such as NAND electrically erasable programmable read-only memories (EEPROMs), a cell-to-cell interference effect (proximal interference effect) increases with shrink of the nonvolatile semiconductor memory devices. A threshold distribution of a memory cell spreads by the inter-cell interference effect in some cases. On the other hand, a multi-valued memory cell such as a multi level cell (MLC) has been proposed. Since a threshold range of each value is relatively narrow in the MLC, a threshold distribution of a memory cell is preferably as narrow as possible. However, when the threshold distribution of the memory cell spreads by the cell-to-cell interference effect, it is difficult to put the threshold distribution of the memory cell within a threshold range of the MLC. In consideration of the cell-to-cell interference effect, a write time is lengthened when the threshold distribution of the memory cell is narrowed.